In the blow-molding of bottles or similar containers, the blow-molding operation results in the formation of a "tail" at the closed end of the bottle, which tail must be snapped off, this generally being accomplished during removal of the bottle from the blow-molding machine. The blow-molding operation also results in the formation of a ringlike collar (known in the trade as a "moil") around the opening to the bottle, which moil is cut off from the molded bottle substantially upon completion of the molding operation. The blow-molded bottles, tails and moils are then generally discharged from the blow-molding machine into a separator to effect separation of the bottles from the moils and tails, which latter components are scrap plastic and can be recycled.
While separation of the moils and tails from the bottles has been a long-standing problem in the blow-molding industry, nevertheless there has been developed a belt separator which has proven highly desirable and efficient for effecting this separation, such belt separator being disclosed in now U.S. Pat. No. 4,593,821, filed April 25, 1985, now U.S. Pat. No. 4,593,821 which application is owned by the assignee of this invention. The disclosure of U.S. Pat. No. 4,593,821, in its entirety, is incorporated herein by reference.
The belt separator disclosed in aforementioned U.S. Pat. No. 4,593,821 discloses a plurality of narrow (preferably round) endless belts disposed in spaced side-by-side relationship, with the upper reaches of adjacent belts being driven by different diameter drive pulleys so that the upper reaches move at slightly different speeds. In addition, the lower reaches are controlled by idler pulleys so that the upper and lower reaches are disposed in close proximity to one another. With this arrangement, it has been discovered that, with a significant number of different shapes and sizes of bottles, effective separation of the bottles can be achieved by carrying the bottles along the belts, with the moils and tails being effectively discharged downwardly between the belts.
Even though the belt separator of the aforementioned application has proven desirable in many use applications, nevertheless it has been observed that less than optimum performance is achieved when this known separator is used with bottles having a certain size and/or shape in relationship to the size or configuration of the moils and tails. For example, when separate bottles having an oval cross-sectional size similar to the size of the moil, it has been observed that the bottles can in some instances move partially downwardly between the belts so that the bottles become trapped between the upper and lower belt reaches. This sometimes requires a momentary shut-down of the separator to effect clearance of the trapped bottles from the belts, and this can undesirably reduce the efficiency and effectiveness of the separation operation.
The present invention relates to a belt separator of the general type disclosed in the aforementioned application, but more specifically is directed to an improvement in said belt separator so as to permit the separator to effect both a rapid and a highly efficient separation of the bottles from the moils and tails, with this separation being capable of performance with an even wider range of sizes and/or shapes of bottles in relationship to the moils and tails, and specifically permitting effective separation of oval bottles from similarly sized moils. The improved separator of this invention in particular has been observed to be more effective in providing the desired separation, and more effective in avoiding trapping of bottles between the upper and lower belt reaches.
In the improved belt separator of this invention, there is employed a plurality of narrow, preferably round, endless belts disposed with the upper reaches thereof in closely adjacent but slightly spaced side-by-side relationship. The adjacent belts are preferably driven at slightly different speeds to effect twisting movement of the bottles and parts which are deposited on the adjacent belts. The endless belts, at the end opposite the drive pulleys, pass over idler pulleys, some of which are designed to function as a vibratory means to cause the upper reaches of some belts to be vertically vibrated or bounced. The vertical vibration of one upper belt reach of each adjacent pair is believed to significantly improve the separating efficiency and at the same time minimize the trapping of bottles between the upper and lower belt reaches, particularly by causing substantially automatic dislodgement of any bottles which have a tendency to be so trapped.
With the improved belt separator of this invention, the vibration of the upper belts is preferably achieved by forming alternate end idler pulleys of a noncircular cross section, with the intermediate end idler pulleys having a circular cross section. The end idler pulleys are all preferably individually freely rotatably supported on an end idler shaft, and the noncircular end idler pulleys preferably have an elongated cross section formed by a pair of lobes which project outwardly in opposite direction so as to achieve the desired vertical vibration of the upper belt reach in response to rotation of the end idler pulleys. In the preferred embodiment, the noncircular end idler pulleys are effectively formed by rectangular blocks which have a length dimension which exceeds the width dimension, with the corners of the blocks being appropriately rounded.
Other objects, purposes and advantages associated with the improved belt separator of the present invention will be apparent to persons familiar with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.